Placenta pain but nothing seen on ultra sound?

Je

Okay so back story about 4 days now I've had a lot of pain in a particular area of my belly. Well had my ultra sound (30 weeks). Well before we started the ultra sound I explained to the tech n dr about the pain and the area ect... so they decided to check it out during my ultra sound and it was the exact location of my placenta. But we look for a while don't see any issue to be visable.

The doctor and tech said even though we didn't see any thing but ofcourse machines are not perfect An could be something minor that couldn't be seen and to keep a eye on it!

Had any one experienced this and what was the out come?